Thanks all who responded to my question yesterday! Stephen R. van den
Berg (srb(_at_)cuci(_dot_)nl) came up with a clue that proved quite right:
Maybe your mail is being delivered on a different machine than where
procmail has been installed. This will cause problems since the
procmail binary may not exist or exist in a different place on the
mailserver, thereby causing your mail to become undeliverable.
I gradually found out by changing the .forward file to just start a
Bourne shell and doing things like `hostname >logfile'. I then did
rlogin to that machine (server A), and was able to look at the system
from that different viewpoint. It turned out that the procmail binary
was correctly found, but would not execute (not even procmail -v). I
then rebuilt it from my personal workstation with -Bstatic. Slightly
better though not usable: procmail -v now caused the word `Killed' to
be displayed. I then tried to rebuild on the mail delivery host (A),
but this proved to hard (no make in the usual places, and no cc
either). I then tried to let the .forward file rsh-execute a wrapper
script on a more sensible server (B), which in turn invokes the
procmail binary. This worked!
I hesitate to use this scheme, as it is a bit complex (I suppose
incoming mail will bounce if the B server is down for some reason).
Anyway, it is always nice when unexpected behaviour can be sorted out.
--Rabbe Fogelholm